Islamic decorative art is one of the most artworks that depends on mathematical drawing systems that shape its decorative units, by constructed them its geometric grids, placed and generated based on certain modular with continuous generative systems. These complex geometrical formations needed time and effort in the past, now a day with CAD (Computer-Aided Design) programs and latest digital techniques, opened a new era of modern Islamic Arts. This research will deal with one of these contemporary digital techniques is the “Parametric Design Method", characterized by its modular system and generative design method. The research focuses on how parametric thinking had emerged in Islamic patterns before the modern digital scientific revolution and generative design programming discovered. And how this mathematical way of inspired many orientalists, artists, and designers in their artworks over art timeline. Hence, there was intellectual compatibility between both sides; the Parametric method and Islamic decorations, especially after the emergence of the use of parametric thought and the spread of its artistic applications.   The main issue that the research monitored is; designers emphasized the common points that combine Islamic art and modern digital techniques and methods by using parametric programming and apply in designs derived from the Islamic heritage to the surrounding environment, without deep analytical parametric study.    In this context, the research presents some points in design methodology based on descriptive analysis, which shows how it is important to use digital techniques for developing the design process with a deep analytical study of the generative modular as well as the ornament itself. The research deals with four main points; Firstly: the study of the parametric design definition.  Secondly: the emergence of using parametric thinking with any inspiration from Islamic patterns in both; design phase, and applied phase. Thirdly: the importance of programming and digital techniques and how to form a contemporary design derived from an Islamic perspective.  Fourthly: a presentation of some contemporary applications of parametric Islamic decorations with a deep analytical understanding of Islamic patterns. In conclusion, the purpose of this research, in general, is to emphasize our need to return to the cultural art heritage, and how to derive from it to do contemporary designs using modern digital technology, in order to do development in the design process.